Biodegradable nanoparticles have received increasing attention as versatile drug delivery scaffolds to enhance the efficacy of therapeutics. Effectiveness of delivery, however, can be influenced by the particle size and morphology, as these parameters can greatly affect the biological function and fate of the material. [Zweers, M. L. T.; Grijpma, D. W.; Engbers, G. H. M.; Feijen, J., J. Controlled Release 2003, 87, 252-254.] Narrowly dispersed particles are highly preferred for use in delivery or sensing applications with respect to monitoring and predicting their behavior as their exhibit a more constant response to external stimuli. [Lubetkin, S.; Mulqueen, P.; Paterson, E. Pesti. Sci. 1999, 55, 1123-1125.]
One disadvantage of conventional methods is the irreproducibility in the size and shape of the particles, since these can be profoundly influenced by the stabilizer and the solvent used. [Kumar, M. N. V. R.; Bakowsky, U.; Lehr, C. M., Biomaterials 2004, 25, 1771-1777.] Another major drawback of conventional biodegradable nanoparticles, based on poly(ε-caprolactone) and other aliphatic polyesters, is the lack of pendant functional groups, which can make physiochemical, mechanical, and biological properties difficult to modify. [(a) Riva, R.; Lenoir, S.; Jerome, R.; Lecomte, P. Polymer 2005, 46, 8511-8518. (b) Sasatsu, M.; Onishi, H.; Machida, Y. Inter. J. Pharm. 2006, 317, 167-174.] The availability of functional groups is a desirable means of tailoring the properties of a particle, including hydrophilicity, biodegradation rate, and bioadhesion.
Therefore, there remains a need for methods and compositions that overcome these deficiencies and that effectively provide functionalized, degradable nanoparticles with reproducibility in particle size and shape.